K T. W IUkkkr and O. (iuovK 87 



branches tlnis cicatcd. hi less severe cases the apical portion of the 

 spur is alone aifectcd, clonuant buds in due course breaking to form 

 fresh growths ; but even in such instances some time must elapse before 

 the spur is once more properly furnished with fruit buds. The variety 

 Tatillac seems particidarly susroptible to the disease in this form ; and 

 trees of this sort at Long Ashtoii are laden with spurs showing this 

 type of damage in all degrees. 



In the other case the first signs of trouble appear in the receptacle 

 of fully opened flowers as jninute greyish -black spots. These rapidly 

 increase in size until they finally coalesce. In a short time the entire 

 receptacle is blackened and the disease spreads to the ovary. As a 

 consequence the fruit fails to set properly and sooner or later drops from 

 the spur as in the type of attack previously described. The main differ- 

 ence between these two forms of attack is that in the case first described 

 the initial points of infection occur in the external whorls of the flower, 

 the disease catching the eye therefore at a very early stage, whereas in 

 the second instance the attack begins on an internal structure of the 

 flower and may escape observation entirely, the failure of the fruit to 

 set properly being attributed wrongly to imperfect fertihsation. 



In both cases the description given applies to examples in which the 

 disease spreads comparatively rapidly through the floral structures ; 

 but under some conditions the extension of the disease proceeds more 

 slowly. Before it has made serious headway the fruit may have set 

 and even have swelled to the size of a pea or larger before the injurious 

 effect puts a stop to further development. Sooner or later, however, 

 the death of the young fruit generally results, although in a few cases 

 signs of attack have been noticed on quite large fruits ; and it is possible 

 that at times an affected fruit may actually reach maturity without 

 serious damage. Such cases are probably infrequent if the disease once 

 establishes a footing. The rapidity of the spread of the disease in an 

 infected flower appears to vary considerably, depending largely upon 

 climatic conditions. Cold, wet weather seems to favour its develop- 

 ment and, conversely, warm dry weather restricts it. Further reference 

 to the influence of various conditions will be made later. 



In addition to these two typical forms of attack a variety of other 

 types has been observed. In some cases the stigma is first aftected, 

 becoming unhealthy and discoloured in appearance. The blackening 

 extends thence downwards through the style to the ovary, the whole 

 pistil eventually turning completely black and failing to develop into a 

 fruit. In other cases small blackened areas appear first on one or more 



